Messages in this thread Patch in this message | | | Subject | Re: [PATCH] VIDEO: ivtvfb, remove unneeded NULL test | From | Andy Walls <> | Date | Sun, 04 Jul 2010 00:11:47 -0400 |
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On Tue, 2010-06-22 at 13:41 +0200, Jiri Slaby wrote: > Stanse found that in ivtvfb_callback_cleanup there is an unneeded test > for itv being NULL. But itv is initialized as container_of with > non-zero offset, so it is never NULL (even if v4l2_dev is). This was > found because itv is dereferenced earlier than the test. > > Signed-off-by: Jiri Slaby <jslaby@suse.cz> > Cc: Andy Walls <awalls@md.metrocast.net> > Cc: Mauro Carvalho Chehab <mchehab@infradead.org> > Cc: Tejun Heo <tj@kernel.org> > Cc: Ian Armstrong <ian@iarmst.demon.co.uk> > Cc: ivtv-devel@ivtvdriver.org > Cc: linux-media@vger.kernel.org > --- > drivers/media/video/ivtv/ivtvfb.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/media/video/ivtv/ivtvfb.c b/drivers/media/video/ivtv/ivtvfb.c > index 9ff3425..5dc460e 100644 > --- a/drivers/media/video/ivtv/ivtvfb.c > +++ b/drivers/media/video/ivtv/ivtvfb.c > @@ -1219,7 +1219,7 @@ static int ivtvfb_callback_cleanup(struct device *dev, void *p) > struct ivtv *itv = container_of(v4l2_dev, struct ivtv, v4l2_dev); > struct osd_info *oi = itv->osd_info; > > - if (itv && (itv->v4l2_cap & V4L2_CAP_VIDEO_OUTPUT)) { > + if (itv->v4l2_cap & V4L2_CAP_VIDEO_OUTPUT) { > if (unregister_framebuffer(&itv->osd_info->ivtvfb_info)) { > IVTVFB_WARN("Framebuffer %d is in use, cannot unload\n", > itv->instance);
Jiri,
You missed an identical instance of the useless test 10 lines prior in ivtvfb_callback_init(). :)
How about the patch below, instead?
Regards, Andy
[PATCH] VIDEO: ivtvfb, fix NULL check
Jiri Slaby reported that stanse found ivtvfb_callback_cleanup has an unneeded test for itv being NULL. itv was initialized as container_of with non-zero offset, so it was never NULL (even if v4l2_dev was).
This fix now checks for v4l2_dev being NULL, and not itv.
Thanks to Jiri Slaby for reporting this problem and providing an initial patch.
Reported-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Andy Walls <awalls@md.metrocast.net> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Ian Armstrong <ian@iarmst.demon.co.uk> Cc: ivtv-devel@ivtvdriver.org Cc: linux-media@vger.kernel.org
drivers/media/video/ivtv/ivtvfb.c | 21 ++++++++++++++++----- 1 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/drivers/media/video/ivtv/ivtvfb.c b/drivers/media/video/ivtv/ivtvfb index 9ff3425..2b3259c 100644 --- a/drivers/media/video/ivtv/ivtvfb.c +++ b/drivers/media/video/ivtv/ivtvfb.c @@ -1201,9 +1201,14 @@ static int ivtvfb_init_card(struct ivtv *itv) static int __init ivtvfb_callback_init(struct device *dev, void *p) { struct v4l2_device *v4l2_dev = dev_get_drvdata(dev); - struct ivtv *itv = container_of(v4l2_dev, struct ivtv, v4l2_dev); + struct ivtv *itv; - if (itv && (itv->v4l2_cap & V4L2_CAP_VIDEO_OUTPUT)) { + if (v4l2_dev == NULL) + return 0; + + itv = container_of(v4l2_dev, struct ivtv, v4l2_dev); + + if (itv->v4l2_cap & V4L2_CAP_VIDEO_OUTPUT) { if (ivtvfb_init_card(itv) == 0) { IVTVFB_INFO("Framebuffer registered on %s\n", itv->v4l2_dev.name); @@ -1216,10 +1221,16 @@ static int __init ivtvfb_callback_init(struct device *de static int ivtvfb_callback_cleanup(struct device *dev, void *p) { struct v4l2_device *v4l2_dev = dev_get_drvdata(dev); - struct ivtv *itv = container_of(v4l2_dev, struct ivtv, v4l2_dev); - struct osd_info *oi = itv->osd_info; + struct ivtv *itv; + struct osd_info *oi; + + if (v4l2_dev == NULL) + return 0; + + itv = container_of(v4l2_dev, struct ivtv, v4l2_dev); + oi = itv->osd_info; - if (itv && (itv->v4l2_cap & V4L2_CAP_VIDEO_OUTPUT)) { + if (itv->v4l2_cap & V4L2_CAP_VIDEO_OUTPUT) { if (unregister_framebuffer(&itv->osd_info->ivtvfb_info)) { IVTVFB_WARN("Framebuffer %d is in use, cannot unload\n", itv->instance);
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